bg-image($url)
  background-image url($url +"@2x.png")
  @media (-webkit-min-device-pixel-ration:3),(min-device-pixel-ration:3)
    background-image url($url +"@3x.png")

    //一行显示,不换行
no-wrap()
  text-overflow ellipsis
  overflow hidden
  white-space nowrap

  //icon点击时增大点击范围
extend-click()
  position: relative
  &:before
    content: ''
    position: absolute
    top: -10px
    left: -10px
    right: -10px
    bottom: -10px
